Instructions

In a large skillet over medium heat, warm the bacon fat. Add the onions, garlic, lower the heat slightly, and cook, stirring once or twice, until very tender, about 20 minutes.
Meanwhile, set a 4 1/2 to 5-quart heavy flameproof casserole or Dutch oven over medium heat. Add the chili-grind beef and cubed chuck, season with salt, and cook, uncovered, stirring often, until meat is evenly crumbled and has lost all pink color, about 20 minutes.
Scrape the onion mixture into the casserole with the beef. Stir in the chili powder, cumin, oregano, and cayenne pepper and cook, stirring, for about five minutes. Stir in the tomatoes and beef stock and bring to a boil. Lower the heat and simmer, uncovered, stirring occasionally, for 1 1/2 hours.
Add pure'd Chilpotle mixture one teaspoon at a time, taste, correct the seasoning, and continue to simmer, stirring often, for another 30 minutes, or until the meat is tender and the chili is reduced to your liking. Stir in the kidney beans and simmer for another 5 minutes.